Lifting truck



Jan. 5, 1954 N. WARSHAW LIFTING TRUCK Filed Feb. 20, 1952 5 Sheets-Sheet l a Sheets-Sheet 2 azii at N. WARSHAW Jan. 5, 1954 LIFTING TRUCK Filed Feb. 20, 1952 3 Sheets-Sheet 5 If 17 g ,3;-

. jiwerzzlorf jVaZ/WZ Warrykaw Patented Jan. 5, 1954 UNITED STATES PATENT OFFICE LIFTING TRUCK Nathaniel Warshaw, Brookline, Mass, assignor to Market Forge Company, Everett, Mass, a corporation of Massachusetts Application February 20, 1952, Serial No. 272,538

4 Claims.

This invention relates to lifting trucks and more particularly to that type of lifting truck customarily used in handling heavy loads which require elevation to and lowering from. substantial heights.

In lifting trucks of this type it is customary to employ upright standards and an elevating platform supported for vertical movement on the standards, the load carrying portion of the elevating platform projecting laterally from the standards. Where substantial heights are present, secondary upright standards vertically movable with relation to primary fixed upright standards are employed in which case the elevating platform is supported for vertical movement on the secondary movable standards.

Heretofore, the load carrying platform and movable standards have been supported for vertical movement either through means of costly precision fit cooperating channels or by means of a pair of vertically offset single rollers operating against the vertical faces of the standards. Due however to the tremendous torque force exerted on opposed faces of the cooperating channels or on the single roller at their respective bearing points on the faces of the standards because of the lateral offset disposition of the heavy load, the cooperating channels frequently jam or become bound or the rollers are caused to score the faces of the standards at the single bearing points until they too jam or become bound with the result that the truck operates improperly or becomes completely inoperative.

The object of the present invention is to provide a lift truck of the character described which will overcome and eliminate the aforesaid disadvantages present in lifting trucks of the prior art and which will reduce to a minimum the friction between the relating moving parts. Another object of the invention is to provide a lift truck of the character described which while insuring the above result will eliminate the necessity of providing means for manual adjustment of the relative movable parts required by slight diifer ences in dimensions due to lack of uniformity in manufacture or the wearing of the parts. Another object of the invention is to provide a lift truck of the character described which will insure the above result while at the same time uprights of standards heights may be utilized without unduly restricting the extent of vertical movement of the platform with relation to the movable standards or the extent of vertical movement of the movable standards with relation to the primary fixed standards.

Other objects of the invention are to provide a lift truck of the character describe which is durable in construction requiring a minimum replacement of parts throughout the normal life of the truck and which is inexpensive to manufacture and to maintain.

In one aspect the invention involves, in a lift truck, an upright standard defining bearing surfaces on its opposite faces, a load platform having a load carrying portion laterally offset from the standard, a pair of vertically elongate beds laterally and vertically offset with relation to each other and pivoted to the load platform adjacent the standard, and endless chain rollers supported on each of said beds and bearing against opposite faces of the standard respectively each bearing against its respective face at a plurality of vertically spaced points, whereby the platform when loaded may be vertically moved on the standards with a minimum of friction. The upper and. lower beds are pivoted to the load platform at respective points respectively above and, below their mid-height.

In another aspect the invention involves, in a lift truck, a pair of spaced fixed upright standards each having an inwardly projecting flange defining a bearing surface, a pair of spaced movable upright standards adjacent the fixed standards movable vertically with relation thereto and supporting a load platform, each movable standard having an outwardly projecting flange defining a bearing surface, the load platform having a load carrying portion laterally olfset from the fixed and movable standards, a vertically elongate bottom bed pivoted to each movable standard adjacent the lower end of said movable standard, a vertically elongate top bed laterally offset with relation to the bottom bed an pivoted to each fixed standard adjacent the upper, end of said fixed standard, and endless chain rollers supported on each of said beds an bearing respectively against the bearing surface of the inwardly projecting flange of the fixed standards and of the outwardly projecting fiange of the movable standards and each bearin against its respective bearing surface at a plurality of vertically spaced points, whereby when the platform is loaded the movable standards may be vertically moved with relation to the fixed standards with a minimum of friction. The bottom and. top beds are pivoted at respective points re spectively below and above their mid-heights.

In still another aspect the invention involves a pair of spaced movable standards each being Z-shaped in cross section and having an outwardly and inwardly projecting leg, each leg defining a bearing surface, pairs of vertically elonsate beds laterally and vertically offset with rela tion to each other and pivoted to the load platform adjacent each of the movable standards, endless chain rollers supported on each of said beds and bearing against opposite faces respectively of the inwardly projecting legs of the movable standard and each bearing against its respectlve face at a plurality of vertically spaced points, and endless chain rollers supported on each of the bottom and top heads bearing -respectively against the bearing surface of the inwardly projecting flange of th fixed standards and the outwardly projecting leg of the movable standards, whereby when the platform is loaded it can be moved vertically with respectto the movable standards and the movable standards can in turn be moved vertically with respect to the fixed standards with a minimum of friction.

For the purpose of illustration a preferred embodiment of the invention lS ShOWl'l in the accon'ip .ny drawings in which 1 is a side elevation of the lifting-truck with th lifting platform :in fully lowered position;

Fig. 2 is an enlarged fragmentaryside elevation of the lifting truck of Fig. l with parts broken away and with the lifting platform in partially elevated position;

3 is a'section along the lines 3-3 of Fig.

Fig. a chain rollers supported on a bed;

Fig. 5 is a reduced fragmentary front elevation of the endless chain .ro'ller 0f Fig. 4; and

Fig. 6 is a schematic drawing of the mechanism for lifting the load'lifting platform and movable standards.

Referring now more particularly to the drawings the numeral I (Fig. 1) represents the liftin trucl: supported on rear 'castors 2 drive wheel 3 and front load supporting wheels 4. Above-the body of the truck is disposed the steering wheel Fifcr controlling the direction of the drive wheel, the operators seat 6, and operating controls I I r controllingthrough conventional commercial motors pumps the operation of a tilting rain 8 2), and a load lifting ram 9.

is a side elevation of one of the endless ght standards l2, interconnected by a cross frame member 59, each having an inwardly projecting is extending vertically throughout the height of the standards, the inner face ill of said flange constituting a bearing surface.

inwardly of the fixed primary standards I?! and disposed in partially nested relation therewith are a pair of spaced secondary upright standards movable vertically with relation to the fixed primary standards and'e'ach Z shaped in cross section comprising a body portion [6 disposed in spaced parallel relation to the adjacent fixed primary standard, an outwardly projecting leg ll having .an outer face [8 disposed in spaced parallel relation to'the inner face of the inwardly projecting flange l3 and constituting a bearing surface,:and an inwardly projecting leg is the opposite faces 29 and 2! of which each constitute bearing surfaces (Fig. 3).

Within the space defined at each side of the lift truck by the fixed primary-standard i2, its inwardly projecting flange 13, the body portion load supporting portion of the truck is 1 faces endless chain 16 of the secondary movable standard it and its outwardly projecting leg ll, are vertically elongate bottom beds 22 (Figs. 2 and i) having fiat vertical side faces and curved end faces, and pivotally mounted at a point '13 below their mid-heights to the outer face of the body portions It; of the movable standards adjacent the bottoms of said standards by suitable means as pivots 2:3. The bottom beds 22 each support about their side and end faces an endless chain roller 25 comprising a plurality of spaced parallel :cylindrical rollers 28, adjacent rollers being connected together at their opposite ends by suitable means here shown in Figs. 4 and 5 as overlapping links 2'! and 2S, pivot pins 29 extending through the links and rollers, and pivot pins 66, intermediate the adjacent rollers, extending only through the links. The pivot pins "28 and 3B are headed at one end 3! and are -38 above their mid-heights by suitable means as pivots 3-3 to plates 3'. carried adjacent the tops of the fixed primary standards l2. Each of said top beds supports about its side and end rollers 33 of identical construction with endless chain rollers 25. fhe endless chain rollers 39 at all times bear against the faces l3 of outwardly projecting legs 17 of the secondary movable standards 5 at plurality of vertically spaced points.

The .load lifting platform (Fig. 3) comprises .spaced'parallel members and 45 disposed inwardly of the secondary movable standards [5,

each member "carrying adjacent said standards a vertical plate :41.

A pair of vertically elongate beds 48 and 49, of identical construction with bottom beds 22 and top beds 35, are laterslly and vertically offset with relation to each other and .are pivotally mounted on vertical plates 4'! by suitable means as pivots so and 5 l the upper bed being pivoted at a point 52 above its mid-height and the lower bed 49 being pivoted at a point 53 below its mid-height. Each of said pairs of upper and lower beds 48 and 49 supports about its side and end faces endless chain rollers 55 and 55 of identical construction with the endless chain rollers'25 and 39. To prevent the endless chain roller -55 from slipping outwardly off the faces of the bed 48, guide plates 43 are mounted on the bed by'suitable means here shown as threaded bolts 44 (Fig. 3). The endless chain rollers 55 at all times bear against the faces 2| of the inwardly projecting legs [9 of the secondary movable standards 15 at a plurality of vertically spaced points and the endless chain rollers 56 similarly bear against the opposite faces 29 of said inwardly projecting legs.

'The'members 45 and 46 of the load lifting platform extend laterally and outwardly beyond both the secondary movable standards I5 and fixed primary standard l2, their spaced extended ends being interconnected by a fiat vertical plate 51 and a further extended angle plate 58. End'plates i59 and'a center plate 60 are fast to the plates 51 and 58 and support a crossbar 6| which in turn carries the spaced outwardly projecting L-shaped load carrying forks 62. The forks are mounted on the cross bar SI for adjustable movement longitudinally of said cross bar by suitable means here shown as sleeves 63 and securing screws I54.

Because of the lateral offset disposition of the forks or load carrying portion of the lifting platform with relation to the movable secondary standards and fixed primary standards, it is understood that when the forks are loaded and in an elevated position from the floor, a tremendous torque force is transmitted through the members 45 and 46, plates 41, pairs of beds 48 and 49 and endless chain rollers 55 and 58 against the opposite faces 2I and 20 of the inwardly projecting legs I9 of the secondary movable standards I5.

This force is distributed over a substantial verti-' V cal portion of said faces at the plurality of vertically spaced points where the rollers of the endless chain rollers 55 and 56 bear against said faces. In the same manner the same torque force is exerted through the secondary movable standards I5, bottom beds 22 and top beds 35, and endless chain rollers 25 and 39, respectively, against the faces I4 of the flange I3 and the faces I8 of the outwardly projecting leg [1, which force is similarly distributed over a substantial vertical portion of said faces.

The mechanism for lifting and lowering the load lifting platform with relation to the secondary movable standards I5 and the secondary movable standards with relation to the fixed primary standards I2 comprises the hydraulic load lifting ram 9 mounted intermediate the secondary movable standards for vertical movement with relation thereto. Forwardly spaced from the ram 9 is an upright guide bar 65 the ram having adjacent its upper end a forwardly projecting sleeve 56 which slidably embraces the guide bar as the ram moves up and down. At each side of the ram and having one end fast adjacent the upper end of the ram are chains 61 each of which extends downwardly and around fixed sprockets 68 (Figs. 3 and 6) thence upwardly and around sprockets 69 (Fig. 2) mounted adjacent the upper end of ram 9, thence downwardly again and around sprockets I0 mounted on opposite sides of a sleeve II (Fig. 3) which slidably accommodates the guide bar 65 and is fast to the cross frame 51 interconnecting secondary movable standards I5 and vertically movable with said standards; thence upwardly and around sprockets 12 mounted adjacent the upper ends of secondary movable standards I5 and thence downwardly to adjacent the vertical plate 51 of the lifting platform where the opposite ends of said chains are secured.

Assuming that the bases of the load lifting fork 52 are resting on the floor in their lowest position, as shown in solid lines in Fig. 1, and further assuming that a load to be lifted is disposed on said forks, raising of the ram 9 will .act through the chains 61 to cause the load lifting platform to rise a corresponding amount on the secondary movable standards I5, the endless chain rollers 55 and 5B travelling freely about their respective beds, a plurality of their respective rollers 25 at all times bearing against the faces 20 and 2| at a plurality of vertically spaced points, thereby to cause a minimum of friction.

This action continues until the load lifting platform has reached the position A shown in dot and dash lines in Fig. 1. At this time continued elevation of the ram 9 causes the load lifting platform to contact a stop at the upper end of the secondary movable standards after which continued elevation of the ram causes the load lifting platform together with the secondary movable standards I5 to rise on the fixed primary standards I2 to the position B shown in dot and dash lines in Fig. 1, the endless chain rollers 25 and 39 travelling freely about their respective beds, a plurality of the respective rollers 26 at all times bearing against the faces I4 and I6 respectively at a plurality of vertically spaced points thereby similarly to cause a minimum of friction. In lowering a load the parts operate in the inverse order of that above described in connection with the elevation of a load.

The fixed upright standards I5 are interconnected by a cross frame I5 and carry adjacent their lower ends forwardly projecting spaced brackets I6 which in turn support a sleeve 11 for pivotally accommodating one end of a shaft I8, the opposite end of the shaft being received in a bearing I9 provided on the forwardly projecting frames II. A tilting ram 8 is connected to the cross frame I5 (Figs. 2 and 3) intermediate the ends of said frame, whereby raising or lowering of the tilting ram 8 causes the fixed primary standards together with the secondary upright standards and load lift platform to tilt forwardly or rearwardly about the shaft I8.

If the load lifting platform is in an elevated and unloaded condition and the fixed primary standards and secondary movable standards are in a rearwardly tilted position it is understood that there will be a tendency for several of the plurality of rollers 26 of the endless chain rollers 56 and 55 which are in bearing engagement with the faces 20 and 2| respectively, to move away from such engagement. To prevent this movement and to maintain the endless chain rollers 56 and 55 in desired bearing engagement, a single guide roll is rotatably mounted on vertical plates 41 by suitable means as pins FBI in spaced relation to and above endless chain rollers 56 and in bearing engagement-with the face 20 of inwardly projecting leg l3.

It will be understood that while the invention is herein disclosed as embodied in a wide lift truck, having a pair of laterally spaced standards, it is equally applicable to a narrow truck in which but one standard is employed.

It should be understood that the present dis closure is for the purpose of illustration only and that this invention includes all modifications and equivalents which fall within the scope of the appended claims.

I claim:

1. In a lift truck, a pair of spaced fixed upright standards each having an inwardly projecting flange defining a bearing surface, a pair of spaced movable upright standards adjacent the fixed standards movable vertically with relation thereto and supporting a load platform, each movable standard having an outwardly projecting flange defining a bearing surface, the load platform having a load carrying portion laterally offset from both the fixed and movable standards, a vertically elongate bottom bed pivoted to each movable standard adjacent the lower end of said movable standard, a vertically elongat top bed laterally offset with relation to the bottom bed and pivoted to each fixed standard adjacent the upper end of said fixed standard; the bottom and top beds being pivoted at respective points respectively below and above their mid-heights, and endless chain rollers supported on each of said beds and bearing respectively against the bearing surface of the inwardly projecting flange of the fixed standards respective bearing surface at a plurality of vertically spaced points, whereby when the platform is loaded themovable standards may be vertically moved with relation to the fixed standards with a .minimum of friction.

2. In a lift truck, a pair of spaced fixed upright standards each having an inwardly projecting flange defining a bearing surface, a-pair of spaced cross section and having an outwardly andan'inwardly projecting leg, each leg defining a bearing surface, a load platform disposed between said movable standards having a load carrying platform laterally offset from both the movable and fixedstandards, pairs of vertically elongate beds laterally and vertically offset with relation to each other and pivoted to the load platform adjacent reach of the movable standards, endless chain rollers supported. on each-of said beds and bearing :against oppcsitefaces respectively of the inwar ly projecting less of the movable standardsand eachbearing against respective face ata plurality of vertically spaced points, vertically elongate bottom beds pivoted to each movable standard adjacent the lower end of said movable standard, vertically elongate top beds laterally offset from the bottom beds and pivoted to each fixed standard adjacent the upper end of said fixed standard, and endless chain rollers supported on each of said bottom and top beds bearing respectively against the bearing surface of the inwardly projecting flange of the standards and the outwardly projecting leg of the movable standards, and each bearing against its respective bearing surface at a plurality of vertically spaced points, whereby when the platform is loaded it can be moved vertically with respect to the movable standards and the movable standards can in turn be moved vertically with respect to the fixed standards with a minimum of friction.

3. In a lift truck, a pair of spaced fixed upright standards each having an inwardly projecting flange defining a bearing surface, a pair of spaced movable upright standards adjacent the fixed standards movable vertically with relation thereto, each movable standard being Z-shaped in cross section and having an outwardly and an inwardly projecting leg, each leg defining a bear ing surface, a load platform disposed between said movable standards having a load carrying platform laterally offset from both the movable and fixed standards, pairs of vertically elongate beds laterally and vertically ofiset with relation to each other and pivoted to the load platform adjacent each of the movable standards, the upper and lower beds of said pairs of beds being pivoted to-the load platform at respective points respectively below their mid-heights, endless chain rollers supported on each of said beds and bearing against opposite faces respectively of the inwardly projecting legs of the movable standards and each bearing against its respective face at a plurality -o ,D of vertically spaced points, vertically elongate bottom beds pivoted to each movable standard adjacent'the lower end of said movable standard, vertically elongate top beds laterally offset from the bottom beds andpivoted to each fixed standard adjacent the upper end of said fixed standard, the-bottom and top beds being pivoted at respective points respectively above and below their mid-"heights, and endless chain rollers supported 'on eachof said bottom and top beds bearing respectively-against the bearing surface of the inwardly projecting flange of the fixed standard and the outwardly projecting legs of the movable standard and each bearing against its respective bearing surface at a plurality of verticallyspaced pointsywhereby when the platform is loaded it can-be moved vertically with respect to the movable standards and the movable standards can in turnbe movedvertically with respect to the fixed standards with aminimum of friction.

.4. In a lift truck, a pair of spaced fixed upright standards each having a flange extending transversely of the body of the standard and defining a bearing surface, a pair of spaced movable upright standards adjacent the fixed standards movable vertically with relation thereto, each movable standard having spaced rear and front legs extending transversely'of the body of the movable standard, each leg defining a bearing surface, a load platform disposed between said movable standards having a load carrying platform-laterally offset from both the movable and fixed standards, pairs of vertically elongate beds laterally and vertically offset with relation to each other and pivoted to the load platform adja cent eachof the movable standards, endless chain rollers supported on each of said beds and bearing against opposite faces respectively of the rear legs of the movable standards and each bearing against its respective face at a plurality of vertically spaced points, vertically elongate bottom beds pivoted to eachmovable standard adjacent the lower end of said movable standard, vertically elongate top beds laterally offset from the bottom beds and pivoted to each fixed standard adjacent the upper end of said fixed standard,

and endless chain rollers supported on each of said bottom and top beds bearing respectively against the bearing surface of the flange of the fixedstandards and the front leg of the movable standards, and each bearing against its 1 spective bearing surface at a plurality of vertically spaced points, whereby when the platform is loaded it-can be moved vertically with respect to the movable standards and the movable standards can in turn be moved vertically with respect to the fixed standards with a minimum of friction.

NATHANIEL WARSHAW. 

